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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.datastax.oss.driver.internal.core.metadata.token;
import com.datastax.oss.driver.api.core.metadata.token.Token;
import com.datastax.oss.driver.api.core.metadata.token.TokenRange;
import com.datastax.oss.driver.shaded.guava.common.base.Preconditions;
import java.nio.ByteBuffer;
import net.jcip.annotations.ThreadSafe;
@ThreadSafe
public class Murmur3TokenFactory implements TokenFactory {
public static final String PARTITIONER_NAME = "org.apache.cassandra.dht.Murmur3Partitioner";
public static final Murmur3Token MIN_TOKEN = new Murmur3Token(Long.MIN_VALUE);
public static final Murmur3Token MAX_TOKEN = new Murmur3Token(Long.MAX_VALUE);
@Override
public String getPartitionerName() {
return PARTITIONER_NAME;
}
@Override
public Token hash(ByteBuffer partitionKey) {
long v = murmur(partitionKey);
return new Murmur3Token(v == Long.MIN_VALUE ? Long.MAX_VALUE : v);
}
@Override
public Token parse(String tokenString) {
return new Murmur3Token(Long.parseLong(tokenString));
}
@Override
public String format(Token token) {
Preconditions.checkArgument(
token instanceof Murmur3Token, "Can only format Murmur3Token instances");
return Long.toString(((Murmur3Token) token).getValue());
}
@Override
public Token minToken() {
return MIN_TOKEN;
}
@Override
public TokenRange range(Token start, Token end) {
Preconditions.checkArgument(
start instanceof Murmur3Token && end instanceof Murmur3Token,
"Can only build ranges of Murmur3Token instances");
return new Murmur3TokenRange((Murmur3Token) start, (Murmur3Token) end);
}
// This is an adapted version of the MurmurHash.hash3_x64_128 from Cassandra used
// for M3P. Compared to that methods, there's a few inlining of arguments and we
// only return the first 64-bits of the result since that's all M3P uses.
private long murmur(ByteBuffer data) {
int offset = data.position();
int length = data.remaining();
int nblocks = length >> 4; // Process as 128-bit blocks.
long h1 = 0;
long h2 = 0;
long c1 = 0x87c37b91114253d5L;
long c2 = 0x4cf5ad432745937fL;
// ----------
// body
for (int i = 0; i < nblocks; i++) {
long k1 = getblock(data, offset, i * 2);
long k2 = getblock(data, offset, i * 2 + 1);
k1 *= c1;
k1 = rotl64(k1, 31);
k1 *= c2;
h1 ^= k1;
h1 = rotl64(h1, 27);
h1 += h2;
h1 = h1 * 5 + 0x52dce729;
k2 *= c2;
k2 = rotl64(k2, 33);
k2 *= c1;
h2 ^= k2;
h2 = rotl64(h2, 31);
h2 += h1;
h2 = h2 * 5 + 0x38495ab5;
}
// ----------
// tail
// Advance offset to the unprocessed tail of the data.
offset += nblocks * 16;
long k1 = 0;
long k2 = 0;
switch (length & 15) {
case 15:
k2 ^= ((long) data.get(offset + 14)) << 48;
// fall through
case 14:
k2 ^= ((long) data.get(offset + 13)) << 40;
// fall through
case 13:
k2 ^= ((long) data.get(offset + 12)) << 32;
// fall through
case 12:
k2 ^= ((long) data.get(offset + 11)) << 24;
// fall through
case 11:
k2 ^= ((long) data.get(offset + 10)) << 16;
// fall through
case 10:
k2 ^= ((long) data.get(offset + 9)) << 8;
// fall through
case 9:
k2 ^= ((long) data.get(offset + 8));
k2 *= c2;
k2 = rotl64(k2, 33);
k2 *= c1;
h2 ^= k2;
// fall through
case 8:
k1 ^= ((long) data.get(offset + 7)) << 56;
// fall through
case 7:
k1 ^= ((long) data.get(offset + 6)) << 48;
// fall through
case 6:
k1 ^= ((long) data.get(offset + 5)) << 40;
// fall through
case 5:
k1 ^= ((long) data.get(offset + 4)) << 32;
// fall through
case 4:
k1 ^= ((long) data.get(offset + 3)) << 24;
// fall through
case 3:
k1 ^= ((long) data.get(offset + 2)) << 16;
// fall through
case 2:
k1 ^= ((long) data.get(offset + 1)) << 8;
// fall through
case 1:
k1 ^= ((long) data.get(offset));
k1 *= c1;
k1 = rotl64(k1, 31);
k1 *= c2;
h1 ^= k1;
}
// ----------
// finalization
h1 ^= length;
h2 ^= length;
h1 += h2;
h2 += h1;
h1 = fmix(h1);
h2 = fmix(h2);
h1 += h2;
return h1;
}
private long getblock(ByteBuffer key, int offset, int index) {
int i_8 = index << 3;
int blockOffset = offset + i_8;
return ((long) key.get(blockOffset) & 0xff)
+ (((long) key.get(blockOffset + 1) & 0xff) << 8)
+ (((long) key.get(blockOffset + 2) & 0xff) << 16)
+ (((long) key.get(blockOffset + 3) & 0xff) << 24)
+ (((long) key.get(blockOffset + 4) & 0xff) << 32)
+ (((long) key.get(blockOffset + 5) & 0xff) << 40)
+ (((long) key.get(blockOffset + 6) & 0xff) << 48)
+ (((long) key.get(blockOffset + 7) & 0xff) << 56);
}
private long rotl64(long v, int n) {
return ((v << n) | (v >>> (64 - n)));
}
private long fmix(long k) {
k ^= k >>> 33;
k *= 0xff51afd7ed558ccdL;
k ^= k >>> 33;
k *= 0xc4ceb9fe1a85ec53L;
k ^= k >>> 33;
return k;
}
}